The present invention relates to an image recording method and an image recording apparatus for recording information such as images, characters, etc. on recording paper, and particularly to a technique for attaining reliable recording while simplifying an image recording step using an image receiving sheet and a toner sheet.
A transfer type image recording apparatus has such a configuration that recording materials such as an image receiving sheet, a toner sheet and so on to be used are stacked and attached on a rotating recording drum and the recording materials are irradiated with laser light in accordance with inputted character/image data so that image recording is performed.
An image recording process in such an image recording apparatus will be described with reference to FIGS. 14(a) to (f) showing an example of recording process for the respective colors of K (black), C (cyan), M (magenta) and Y (yellow). Each process for the four colors K, C, M and Y is constituted by a step of performing laser recording with corresponding color data, and a step of separating a toner sheet from an image receiving sheet thereafter. When laminating is performed, a laminating step will be inserted before each step of laser recording. The respective steps will be described below sequentially.
An image receiving sheet 5 is wound on a recording drum 2 as shown in FIG. 14(a).
A K-toner sheet 6 is wound on the image receiving sheet 5 as shown in FIG. 14(b) in order to execute a K-process.
Laser light is radiated in accordance with image/character data of K so as to perform recording as shown in FIG. 14(d).
The K-toner sheet 6 is separated from the image receiving sheet 5 as shown in FIG. 14(e) (the K-process is terminated).
Next, a C-process is executed. That is, a C-toner sheet is wound on the image receiving sheet in the same manner as in the K-process.
Laser recording is performed in accordance with C-data.
The C-toner sheet is separated from the image receiving sheet (the C-process is terminated).
Next, an M-process is executed. That is, an M-toner sheet is wound on the image receiving sheet in the same manner as in the K-process.
Laser recording is performed in accordance with M-data.
The M-toner sheet is separated from the image receiving sheet (the M-process is terminated).
Next, a Y-process is executed. That is, a Y-toner sheet is wound on the image receiving sheet in the same manner as in the K-process.
Laser recording is performed in accordance with Y-data.
The Y-toner sheet is separated from the image receiving sheet (the Y-process is terminated).
In such a manner, the four colors K, C, M and Y are put one on another or not put on the image receiving sheet properly so as to form a desired color image as shown in FIG. 14(f).
The color image formed through the above process is transferred to recording paper (not shown).
In the case where laminating processing is required, the toner sheet is pressed by a press roller, a heating roller or the like immediately before laser recording in each color so as to be put into tight contact with the image receiving sheet as shown in FIG. 14(c).
However, in the above-mentioned recording process, the image receiving sheet is detached from the image recording apparatus after image recording of the four colors K, C, M and Y is performed on the image receiving sheet, and then the image receiving sheet is attached to another apparatus so that an image on the image receiving sheet is transferred to recording paper. Therefore, there has been a problem that during the transfer, there is an increased possibility that the recording material will become damaged or stained with dust when the image receiving sheet is detached from the image recording apparatus. This causes lowering of the quality of the recording material. A step of transferring the image to recording paper by another apparatus, that is, a step of detaching the recording material from the image recording apparatus and attaching it to a transfer apparatus is required in addition to the image recording step. Therefore, there has been a problem that the number of steps working increase so that the cost increases.
In addition, generally, there is a slight variation in the thickness of recording paper in accordance with a location of the recording paper. This variation occasionally influences the image quality. That is, the height of the image receiving sheet and the toner sheet which are attached to the recording drum through the recording paper from the drum surface varies in accordance with the thickness of the recording paper. On the other hand, an optical head for emitting laser light has a fixed focus. Accordingly, when the thickness of the recording paper varies, the focal position of the laser light may be out of its proper position, so that the laser light spot is extended. As a result, there has been a problem that the resolution of a recorded image deteriorates so that the image quality deteriorates.
It is therefore an object of the present invention to provide an image recording method and an image recording apparatus in which not only an image recording process can be simplified to improve the productivity, but also image recording on recording paper can be performed accurately and stably with high quality.
In order to achieve the above object, according to the present invention, there is provided an image recording method comprising the steps of:
attaching recording paper on an outer peripheral surface of a recording drum;
forming an image receiving layer on a surface of the recording paper; and
transferring the toner on a toner sheet onto the image receiving layer to record an image thereon in accordance with recording data.
In this image recording method, recording is performed by selectively transferring toner to the image receiving layer on the recording paper in accordance with the recording data. Therefore, an image is recorded on the recording paper directly, so that the image recording process is simplified.
According to the present invention, a cushion layer is formed between the surface of the recording drum and the image receiving layer.
In this image recording method, a cushion layer is formed under the image receiving layer on the recording paper, so that the cushion layer sinks in accordance with the thickness of toner and the surface to which the toner is transferred is made flat. Accordingly, it is possible to improve the adherence of the toner, and it is possible to prevent toner from separating after transfer, so that image recording can be realized with higher quality.
According to the present invention, the receiving layer is formed by attaching an image receiving sheet having the image receiving layer on the surface of the recording paper and then transferring the image receiving layer thereon.
In this image recording method, the recording paper and the image receiving sheet are attached subsequently on the outer circumferential surface of the recording drum, and the image receiving layer of the image receiving sheet is transferred to the outer circumferential surface of the recording paper. The toner sheet is further wound thereon, and toner is thermally transferred to the recording paper directly in accordance with the recording image data to thereby record an image thereon. Accordingly, image recording onto the recording paper is performed directly, stably and more accurately. In addition, the image receiving sheet in which an image has been formed is not required to be detached from the image recording apparatus and transferred to the recording paper again. It is therefore possible to simplify the image recording process.
According to the present invention, the image receiving sheet includes a cushion layer therebeneath, and the image receiving layer is transferred such that the cushion layer is placed between the surface of the recording paper and the receiving layer.
In this image recording method, a cushion layer is formed in the image receiving sheet, and is transferred to the recording paper. It is therefore possible to form a cushion layer in the recording paper easily.
According to the present invention, a protective layer is formed on an image recorded surface on the recording paper.
In this image recording method, a protective layer is provided on the image recorded surface after the toner is transferred, so that the recorded toner or the recording paper itself is protected from external damage. It is therefore possible to prevent image quality from deteriorating as much as possible after recording.
According to the present invention, the toner sheet includes a light-heat conversion layer, and the toner is thermally transferred by irradiating laser beam onto the light-heat conversion layer.
In this image recording method, thermal transfer is performed by use of laser light, so that it is possible to record image data faithfully at a high speed. It is therefore possible to perform high-quality image recording easily.
According to the present invention, the image recording method further comprises the steps of: measuring thickness of the recording paper by thickness detecting means; and adjusting focal point of the laser beam in accordance with the measured value of the thickness detecting means.
In this image recording method, it is possible to correct the displacement of the focal position of the laser light caused by variation of the thickness of recording paper which is generally uneven. It is therefore possible to perform high-quality image recording stably without reducing the resolution of the recorded image.
According to the present invention, a non-contact type displacement meter is used as the thickness detecting means.
In this image recording method, it is possible to detect the thickness easily and accurately at a high speed.
According to the present invention, a laser displacement meter is used as the thickness detecting means.
In this image recording method, the laser displacement meter is used for detecting the thickness of the recording paper, so that the information of the thickness can be obtained accurately through the laser displacement meter is of the non-contact type. In addition, the response speed of the meter is so high that it is possible to terminate the thickness detection quickly. In addition, it is also possible to correct the focal position while performing the thickness detection.
According to the present invention, the thickness of the recording paper is measured from a position opposite to the rotating direction of the recording drum, and the focal position of the laser beam is adjusted in real time.
In this image recording method, the time lag between the time to detect the thickness and the time to analyze the detection result can be canceled. Accordingly, it is possible to adjust the focal position in real time and thereby it is possible to perform image recording quickly without increasing the time for recording an image.
Alternatively, the measured value of the thickness detecting means with respect to all the predetermined detection area may be once stored in memory means. The focal point of the laser beam is subsequently adjusted in accordance with the stored value.
According to the present invention, there is provided an image recording apparatus for recording an image by use of any one the above image recording methods.
In this image recording apparatus, it is possible to perform image recording, so that it is possible to simplify the image recording process and improve the productivity, and it is possible to perform high-quality image recording onto the recording paper stably and accurately.